1. Field of the Invention
The invention relates generally to integrated circuit devices, and particularly to configuring an integrated circuit that utilizes a low pin count.
2. Description of the Related Art
With the need to provide a common integrated circuit for multiple purposes and to help facilitate unit testing, integrated circuits are commonly designed to function in different modes of operation. The parameters that dictate how the integrated circuit is to function are called a configuration vector and include settings such as input/output bus port width, pad drive strength, test mode, and any functional sub-modes.
During a power-on-reset sequence, a circuitry utilizes a reset configuration vector to specify operating parameters. In some devices, the reset configuration vector is communicated to the circuitry through a set of external pins (typically 4-8) that are driven high or low. These same devices require a relatively costly external integrated circuit to isolate the circuitry pads from the power-on-reset level drivers.
Manufacturers, in a goal to produce smaller and more powerful products, have limited space in their products for integrated circuits. Therefore, in addition to being economically costly, the external integrated circuit consumes board real estate that might not be available or that could be utilized for other functions.
Integrated circuits are becoming increasing complex and are requiring more and more pins to expose this functionality to external circuitry. The number of pins that may be utilized for establishing the configuration vector is decreasing.
To reduce the relatively costly external integrated circuit to establish the configuration vector and to handle the decreasing number of pins available, there exists a need for a new and improved method and apparatus for specifying the configuration vector for a system implemented on an integrated circuit.
In the following detailed description of exemplary embodiments of the invention, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration of specific exemplary embodiments in which the invention may be practiced.